Yes, Pietra Grey ceramic can be used outdoors. Ceramic tiles are durable and resistant to moisture, making them suitable for outdoor applications such as patios, porches, and pool areas. However, it is important to note that specific installation requirements and proper sealing may be necessary to ensure the longevity and performance of the tiles in outdoor environments. It is advised to consult with a professional tile installer or manufacturer for more information on the suitability and installation requirements of Pietra Grey ceramic outdoors.